1. Field of Invention
This invention relates to liquid leak detectors, specifically those utilized to detect water leakage from plumbing fixtures in a typical household or business.
2. Prior Art
Household plumbing leaks are a common problem. When they go undetected for any length of time the damage and resultant expense can be considerable. A typical household can easily have a dozen or more places where such leaks are likely to occur.
Prior art detectors for such leaks fall primarily into two categories: electro-mechanical and entirely electronic. Electro-mechanical devices typically involve the use of some type of float with an actuator switch to an alarm. U.S. Pat. No. 6,414,598 to Freill (2000) discloses a device of this means.
The more common detectors available on the market today are completely electronic and use some variation of probes or strips with conduction sensing circuits to activate an alarm. U.S. Pat. No. 5,091,715 to Murphy (1992) and U.S. Pat. No. 4,297,686 to Tom (1981) are typical of such embodiments.
Both types of detectors suffer from the same limitation: they require a reliable source of electrical power—usually supplied from a conventional battery. This introduces a significant disadvantage, since now, not only must the device monitor for leaks; it must also monitor its own power source and activate the alarm if the battery gets weak. Descriptions of such prior art reveals that the battery monitoring circuit is often times more complex than the leak detection circuit itself. A dozen or so of these type of detectors located throughout the home, with batteries failing at random intervals, is not a desirable solution.
Other prior art for liquid leak detection systems focus primarily on industrial applications and tend to be complex and elaborate, and as such not practical or economical for household use. Representatives of such prior art are:    U.S. Pat. No. 5,655,561 Wendell    U.S. Pat. No. 5,539,383 Chin    U.S. Pat. No. 4,800,372 Poteet    U.S. Pat. No. 4,598,273 Bryan    U.S. Pat. No. 5,058,421 Alexander    U.S. Pat. No. 4,805,662 Moody    U.S. Pat. No. 4,246,575 Purtell